Update mod_tile to renderd protocol to version 3.

Include an "options" string and a "mimetype" string.
Support options for tile layers in mod_tile.

If a tile layer has options enabled, the URL changes to

http://localhost/style/options/z/x/y.ext
Extend the storage backends to support options
Enable mapnik style parameterization

Provide a parameterization function for internationalizing the names